Syren Sinks
by RockSunner
Summary: What if Syren made better use of her underwater advantage when Ladybug came after her alone?
1. Sunk

What if Syren made better use of her underwater advantage when Ladybug came after her alone?

 **Syren Sinks**

 **Chapter 1: Sunk**

Marinette and Alya slipped into the theater just in time for the opening credits of the movie, _Mecha Monkey vs. Cyber Shark 3_. Max, Markov, Rose. Juleka, Kim, Nino, and Alix were already there.

Both Marinette (as Ladybug) and Alya (as Rena Rouge) had been delayed, stopping a mass escape of animals from the zoo. (It was thought to be the work of terrorists, and not Hawk Moth this time). Marinette had been further delayed returning the Fox Miraculous to Master Fu, and taking time to help him work on a formula to feed the kwamis so they could grant underwater breathing to their Miraculous holders.

"Hi!" said Rose, waving at them.

"Hey!" said Nino.

"Sorry...sorry...sorry," said Marinette, aware of the glares of the movie patrons she was disturbing.

As the James-Bond-like theme began to play, the people in the seats ahead of them jumped up and ran away.

"What's going on?" asked Marinette.

In an instant she knew. Water flooded beneath them, making them all raise their feet.

"Okay, who left the faucet running?" asked Alya.

Water was pouring in from the lobby above, as well as below. Marinette realized there was only one way out.

"The stairs! Quick!" Marinette shouted. "Everyone, up on the roof!"

* * *

All of them got to the roof, where they had a view of the flooded city. Paris was deep underwater, with only roofs and floating cars visible.

"My circuits are sensitive to water," the little robot Markov told Max.

It had to be the work of an akuma villain, Marinette thought. She had to get away and transform.

"Woo-hoo!" Kim jumped into the water, laughing happily. "Come on, guys! I can teach you to swim in two seconds flat, Markov. You just put your arms like this, then you push your legs, and it's kind of like being a frog, you see. In fact, it helps to think like a frog, too, you know..."

A mermaid leaped out of the water and slammed down on Kim, forcing him below the surface.

"Kim!" cried Max.

Marinette slipped away and found a trash bin floating nearby. She grabbed a shovel that a workman had left on the roof, and pulled the bin close enough to get in. She set off in the bin, using the shovel as a paddle.

"Marinette, what are you doing?" shouted Alya from the roof.

Marinette froze for an instant. She had hoped to get away unseen.

"Umm, I'm gonna get help," said Marinette, waving awkwardly.

The action unbalanced Marinette's crude boat and she went over into the water.

She pulled herself back out and got the bin going again, saying, "I'm fine!"

Alix mumbled something sarcastic she couldn't quite hear.

Marinette didn't care – she knew she was the help that would save the day.

* * *

"Okay, we're alone," said Marinette to the kwami in her purse. "Tikki, spots on!"

She transformed to Ladybug. She always felt like dancing when she did this, but there was no chance for that in the makeshift little boat.

Ladybug took a deep breath and swam through the devastated city. There were cars floating everywhere. She was nearly swallowed by a giant catfish. As she came up for air, she realized how hard this was going to be.

She wouldn't give up. She took two more deep breaths and went down again. Luck was with her this time. She spotted the mermaid and Kim swimming together. Kim had a bubble like a diving helmet around his head. It seemed the villain had charmed him – he was going with her willingly.

"Huh! This is amazing, Syren! I can breathe underwater, just like a fish," said Kim.

"I knew you'd love it, and I've got lots of other surprises for you, you'll see..." said Syren.

Ladybug used her yo-yo to snag Kim's foot and pull him back away from her.

"Hey!" said Kim.

"My Prince!" said Syren, swimming after Kim.

Syren caught him and swam away, towing Ladybug by the yo-yo line she had attached to Kim's foot.

Ladybug was running out of air. She clung to an ornamental iron window grille to keep from being dragged deeper.

A butterfly-shaped line of light formed around the akuma victim's eyes. The mermaid nodded and charged at Ladybug. For an instant it looked like she was going to punch Ladybug out of the water, which would have been a good thing.

Instead, the mermaid punched lower, knocking the remaining breath out of Ladybug. Ladybug nearly passed out. She was helpless, choking and drowning.

The mermaid pulled the grille from the window with supernatural strength and wrapped it tightly around Ladybug's upper torso. She pulled Ladybug's right hand out through one of the circular loops in the grille, then bent the metal circle until it clamped around her wrist. Ladybug was shackled to the heavy iron weight. The mermaid reached up to her ears and took the earrings. As Ladybug detransformed, Syren let her sink.

No strength, no air, weighed down – Marinette was going to the bottom. She was going to die. Why hadn't she tried to find Chat Noir first, or gone back to Master Fu and helped him finish the underwater formula?

Kim stared as she sank. He said, "Hey! I know her. Marinette goes to my school. Don't kill her. She's nice."

Syren swam up to Marinette and caught the grille around her. She blew a large bubble of air, which she placed around her face. She bent the grille open and set Marinette free.

"Drowning you in front of Kim would make me look bad," Syren said. "I have a better idea. You can be my hostage to lure Chat Noir down here. Don't try anything. You're completely dependent on me for air.''

"I won't try anything. I surrender," said Marinette.

For the moment, Marinette was just glad to be able to breathe again. Escape plans could come later.

"You're coming with us to the swimming pool," said Syren. "I'm going make a throne for my Prince. You can help, slave."

"Yes... Mistress," said Marinette.


	2. Waterside Chat

**Chapter 2: Waterside Chat**

Chat Noir waited for Ladybug at one of their rooftop rendezvous points. He waited a long time. She didn't appear.

He didn't want to go into the water alone.

He began to dwell on the secrets Ladybug was keeping, and on the mysterious "Him." Someone who managed Rena Noir's Miraculous when she wasn't using it. Someone Chat wasn't trusted to meet or know anything about.

"Is Ladybug with Him now?" Chat thought. "Is that why she hasn't shown up?"

"This is so dumb!" he said aloud. "Claws in."

"What's taking her so long?" asked Plagg impatiently.

"Maybe the mysterious 'Him' gave her another Miraculous with water-based powers to hand off to someone."

"No comment. And I still can't be bribed," said Plagg.

"How about threatened? What if I just order you processed American cheese from now on?" asked Adrien.

"Too cruel! You would never do that," said Plagg.

"Right. I have a better plan," said Adrien, beginning to pull the silver ring off of his finger.

"Whoa, easy! W-What are you doing?" asked Plagg.

"If you don't tell me what Ladybug is hiding from me, I'm _done_!" said Adrien.

"You can't do that!" said Plagg.

"Why not? No one'll know if I quit. No one'll care!" said Adrien.

" _I_ will!" said Plagg.

"Why? Because you won't have anyone to give you Camembert?" asked Adrien

"Oh, I'm sure there'll be another Cat Noir to give me cheese..." said Plagg. "But he won't be you."

Adrien's expression softened, and he slid the ring back unto his finger.

"Plagg, I have a question. Why does my ring suddenly feel so wet? Did you do that?"

"That's a very bad sign. There's a connection between your Miraculous and Ladybug's. It means her Miraculous has been underwater for a long time."

"How long?" asked Adrien.

"Over an hour," said Plagg.

"Ladybug can't stay underwater for an hour," said Adrien.

"I know," said Plagg. "That's what worries me. Not everyone could get to high ground. People have drowned from this already."

"The Miraculous Ladybug cure will fix that," said Adrien.

"If she wasn't one of the ones who drowned," Plagg said.

"Don't say that! Of course she didn't drown. She would power up and swim to safety," said Adrien.

"What if she didn't have her Miraculous on her, and was cut off from it by the water?" asked Plagg.

"She must wear it all the time, like I do," said Adrien.

"Not necessarily. Ladybug might wear different earrings sometimes in civilian form, to protect her identity."

"I still refuse to believe it. But we've got to do something to help Ladybug."

"Transform and swim around?"

"That's hopeless. Paris too big and too flooded to find her alone. Here's what I want. You know where the guy is, the one Ladybug called 'Him'. I know you can't lead me to him without permission. But you can go to him and persuade him to help. I'll wait here."

"I wouldn't do it ordinarily... but that wet ring has me worried that something happened to Tikki."

* * *

More waiting.

Adrien had been bluffing when he said he was done. He couldn't leave Paris and Ladybug in danger like this. If Plagg showed up alone, Adrien would transform and go searching everywhere, hopeless or not.

"Hello, Chat Noir," said a voice behind him.

Adrien spun around and saw an old gentleman with a goatee, wearing a Hawaiian shirt. He had come up so quietly that Adrien had not been aware of his presence until he spoke.

On seeing the man, memories flashed through Adrien's mind of the old man he helped to stand when the man dropped his cane. It cost him his first day at school.

"You! You're the man who..."

"I am Master Fu. I'll explain everything, I promise. Right now, I need your help with something."

Master Fu held up a vial with a green fluid.

"This only needs one ingredient, and it will let you breathe underwater and help Ladybug. The secret ingredient is a tear of joy."

"A tear of joy?"

"I've tried everything: water from the Laughing Fountain, melted snow from the Mountain of Jubilation, drops of pure chocolate extract. Nothing has worked. I have failed."

"Have you tried a real tear of joy?"

"What?"

Adrien focused on his memories of Ladybug. The way she smiled, the effortless and beautiful way she moved, and on how much he loved her.

Tears came his eyes. He wiped one onto his finger.

"Try this," said Adrien.

Master Fu opened the vial and let Adrien drop in the tear. There was a flash of light and a jet of magical smoke from the top of the vial.

"I think you have just found the magic ingredient," said Master Fu. "Plagg, come here."

"Oh, no! I hate transforming!" said Plagg.

Plagg drank the formula.

"Now, tell him to power up," said Master Fu.

"Plagg, power up!" Adrien commanded.

The kwami glowed. His long tail flattened into a green eel-like version. His front paws became fins.

"Aqua-Plagg," he said sheepishly.

"Now say, 'Aqua-Plagg, fins out'," said Master Fu.

"Aqua-Plagg, fins out!"

Adrien transformed into a sleeker, more water-friendly version of his Chat Noir costume, with flippers on his feet and an eel-like tail.

"Now you can breathe underwater," said Master Fu. "Please find out what has happened to Ladybug."

"I'll tuna in, and find out whatever's fishy around here!" said Chat. "I'm Catfish Noir!"

He dived deep into the water.


	3. Chat Fishing

**Chapter 3: Chat Fishing**

Chat Noir hunted underwater for Ladybug. Even with new aqua powers it was still an enormous task to search a flooded city. He checked his baton for anything that might help.

Once Ladybug had found Chat when he was captured by Copycat – there was a GPS locator in her yo-yo. He found a similar locator in his staff, and it was waterproof.

The location was the swimming pool in the vicinity of the school. That made sense. The akuma villain must love to swim, or something.

* * *

Chat Noir looked in through the glass top of the pool building.

At one end of the pool, an informal throne had been made by decorating the lifeguard's seat with pool noodles. Artificial plants were arranged artistically around it. Kim was sitting on the throne, with a big bubble of air around him. Floating near the bubble was the mermaid akuma.

From above, Chat could see that some of the artificial plants had been arranged in the form of an arrow. It pointed toward the back of the throne. There was Marinette, with a bubble of air around her head!

What was she doing here, and where was Ladybug? Chat would have to be careful since the akuma had hostages.

Chat Noir would sneak Marinette out first. He suspected her bubble wouldn't last without akuma magic sustaining it. He needed a way to supply her with air. His modified baton held the answer: split in two, one side could be widened out into a magical breathing mask.

Marinette looked up and saw Chat. She made a gesture to be quiet, not daring to put her finger to her lips for fear of breaking the bubble, but moving her finger in front of the bubble as close as she could.

Chat Noir was familiar with the pool entrances and knew he could reach Marinette through the shower and locker rooms on that side of the building. Entering very quietly, he swam to Marinette while the akuma was distracted with Kim.

"I'm _your_ Syren now. And you could be my merman," said the mermaid. "It only needs a kiss, and you'll become just like me!"

"You mean _I_ could swim as fast as you?" asked Kim.

"Yes, Kim! You'll be my Prince, and we'll rule this underwater city together, forever!"

Kim puckered his lips and almost kissed her, then drew back.

"Wait! Does this mean I never get to see _Mecha Monkeys vs. Cyber Sharks 3_?"

"What?!" said Syren.

Syren thought a moment. Once he kissed her, she would control him. Any promise could be broken...

"I'm sure we can find a way to project it underwater. We can watch it together," said Syren.

"Okay, then," said Kim.

He kissed her, and a bright pink light spread around him, shaping him into a merman with pink skin and horns like hers.

* * *

While Kim and Syren were caught up in the moment, Chat Noir swam away with Marinette.

Out of Syren's spell range, the bubble around Marinette's head broke up and she was without air again. Chat was ready with the baton breathing mask. Marinette pressed it to her face.

They got safely to the surface and Chat Noir helped Marinette onto a roof. She gave him a grateful hug.

"Thank you! Thank you so much, Chat Noir!" said Marinette. "You have underwater powers... you met Master Fu, didn't you?"

"Yes, I... Wait, how did you know about him? Did Ladybug tell you? Where is she?" asked Chat Noir.

"Ladybug... is me. Or was me, because Syren got my Miraculous," said Marinette.

"It's really you, M'Lady?"

"Yes. I made the mistake of attacking her alone without enough air left. She almost drowned me. She took me hostage instead, and made me her slave to build that throne. I arranged the plants to help you spot me from above."

"You're okay now. We can go to Master Fu, and get more of the water breathing formula for you..."

"That's no good without my Miraculous. The formula powers up kwamis, not people."

"What can we do?"

"It's up to you this time, Chat Noir," said Marinette. "You have to get my Miraculous back before Syren gives it to Hawk Moth."

"With no Ladybug and no Lucky Charm..." said Chat Noir.

"You can do it, Chat," said Marinette. "I have complete faith and trust in you."

"Very well, M'Lady," said Chat. "Without a trout, I'm going Chat-fishing."

"Chatfish" dived back into the water.

* * *

Syren and Kim the merman kissed and cuddled.

A line of light formed around Syren's face, demanding her attention.

Hawk Moth sent an angry message to Syren. "You're getting distracted from my mission. Are you prepared to face Chat Noir? Where is your hostage?"

"She's right over..." said Syren, pointing to the side of the throne. "Wait... where did she go?"

Kim and Syren swam around looking for Marinette.

"Incompetents!" sent Hawk Moth. "While you two were playing kissy-face, she got away!"

"Kim and I will find her," said Syren.

"Yeah!" said Kim. "I'll help you... but who are you talking to?"

"Forget that. I want you to bring me Ladybug's Miraculous right now," said Hawk Moth.

"What if I don't?" asked Syren. "I am Queen here. Why should I take orders from a land creature?"

"I can remove your power. Your love story will be sadly star-crossed, when you have to come up for air every few minutes and your mate cannot live on land."

Syren looked sad and angry. "You win, I'll bring you the earrings."

Hawk Moth sent her swimming directions to the half-flooded mansion.

When the connection dropped, Syren said to Kim, "I have to go to Hawk Moth – I don't trust him. Follow me, but don't come into his lair. If anything bad happens, I'll yell for you to go. Then swim for help as fast as you can."

"I wanna be by your side and protect you, Syren," said Kim. "I won't leave you."

"I am your Queen and those are my orders," said Syren.

"Yes, my Queen," said Kim in an obedient monotone.


	4. Bug Battle

**Chapter 4: Bug Battle**

The window in the attic of the Agreste Mansion was still above the water line. Syren did a flying leap through the open center pane, and landed in the meter-deep water inside that had leaked up from the flooded floors below.

Hawk Moth waded to her, a cold look on his face. "The Miraculous, if you please."

"Here!" said Syren, holding out the earrings in her hand. "Now leave me and Kim alone."

Hawk Moth grabbed them.

"I have no intention of doing that. You two failed me badly by not getting the other Miraculous. I'll find someone else to get it – you're fired. Return to me, my little akuma."

The purple and black butterfly freed itself from the secrets bracelet on Syren's left wrist. A cloud of purple energy formed around her, transforming her back to Ondine. The butterfly flew into the glass bubble on the top of Hawk Moth's cane.

Unlike when an akumatized object was broken by Ladybug, Ondine retained all of her memories of what she had done as a villain. She lunged up out of the water, enraged and ready to attack Hawk Moth.

Hawk Moth drew the sword from his cane and stabbed her in the chest.

"Kim! Get help!" Ondine shouted as she collapsed.

"Fly out of my cane, my little akuma, but stay close," said Hawk Moth. "Dark wings, fall!"

With the sword vanished from her wound, Ondine started bleeding out rapidly.

Gabriel Agreste put on the earrings (they attached by magic with no need for piercings).

"Spots on!"

"Now I am Hawk Bug," said the villain clad in a red costume with black polka-dots. "Lucky Charm!"

He received a butterfly net with a polka-dotted handle. He would use it to catch the akuma butterfly rather than the unfamiliar yo-yo. He would purify it. After that, he would cast the charm that would restore the world to normal. It might even heal the girl, though he didn't care one way or the other about that. He would get rid of all this inconvenient water, which had flooded his wife's coffin chamber below.

* * *

Chat Noir had gone back to the swimming pool to confront Syren and Kim, but they were gone. Now he was swimming through the flooded streets, trying to pick up their trail.

Merman Kim came swimming up fast. Chat readied his staff and braced for an attack.

"Chat Noir! You gotta help Syren!" said Kim. "Hawk Moth turned on her!"

"Lead the way, merman," said Chat Noir.

They swam together back to a mostly-submerged walled mansion.

"Hey, I know this place..." said Chat.

"No time for memories, man. Get in there and help Syren! I'll follow," said Kim.

Chat leaped out of the water and used his expanding staff to land gracefully inside.

For a second he thought he saw Ladybug with his back to him. But the voice that called out as a butterfly net was tossed into the air was not hers.

"Miraculous Hawk Bug!"

A swam of magical butterflies removed the flood water from the room and from all of Paris. Ondine was no longer wounded, but she was still unconscious from the shock. Kim transformed back and was left sitting on the lawn. He jumped up and looked for a way into the mansion.

Chat raised his staff and called out, "Got you now, Hawk Moth! You're about to time out."

"Hawk Bug at the moment," said the villain, turning to face him. "You haven't got me yet. Security systems on!"

"Permission denied," said a computer voice. "Form not recognized as an authorized user."

"I still have powers for a few minutes more! Ladybug can always beat Chat Noir."

Hawk Bug threw out his yo-yo, which missed.

"Not used to your powers yet, Bugsy?" asked Chat Noir. "Too bad I won't give you time to turn back to your favorite form."

Chat charged at Hawk Bug, but stumbled on his flippers.

"Too bad your water form is a handicap on dry land," replied Hawk Bug. "I'll make you tell me how you got that extra power, once I beat you."

"A little fish told me how," said Chat.

Hawk Bug threw his yo-yo again, and this time entangled Chat Noir around the legs and pulled him down.

"I'm getting the hang of this," said Hawk Bug. "Instinctive knowledge of how to use the weapons comes with the suit. But your instincts are for water fighting right now, so you lose."

Chat Noir tried to free his legs as Hawk Bug started to pull him in. It would have been easy in his normal hero form, but the foot flippers were getting in the way. One chance. Marinette said the potions empowered the kwamis, not the people. If he put Plagg back to normal...

"Plagg, power down!"

It worked, almost as expected. Aqua Chat flashed back to civilian form for an instant before going back to regular Chat Noir. He slipped the loop of yo-yo line off his feet.

"Adrien?" said Hawk Bug in shock. "I never meant to hurt you. This has always been about getting your mother back, for both of us."

"You have hurt me, and you've lost me!" said Chat Noir in a rage. "You've hurt so many people! You're a monster!"

"I'm your father," said Hawk Bug, backing away and swinging his yo-yo as a shield as Chat charged. "I demand you listen to me and obey me."

"No! You're not my father any more!"

Chat extended his staff and got it into the path of the spinning yo-yo, causing it to wrap around the pole. He yanked the villain off-balance into a punch.

As Hawk Bug fell back, Ondine jumped to her feet. She grabbed Hawk Bug around the neck with one strong swimmer's arm and removed his earrings with her free hand.

Hawk Bug detransformed and Ondine slammed him to the ground.

"That's for what you did to me and my friend Kim!" said Ondine.

* * *

After they called the police and got Gabriel Agreste arrested for kidnapping and terrorism, Chat Noir went back to Marinette and returned her earrings.

"Thank you! I knew you could do it," said Marinette.

"I had an little help from some friends," said Chat. "Now that I know who you are, I'd like you to know who I am, too."

"Do you really think that's wise?" asked Marinette.

"I think so. Secrets between us have almost ruined us. No more secrets," said Chat. "Claws out."

"Adrien!"

"Yes, Marinette."

"Did you know I had you on a crush... I mean a crush on you... all the time I was pushing you away as Ladybug?"

"I thought you were a star-struck fan," said Adrien.

"No, I started liking you for your kindness, when you gave me your umbrella. I never would have fallen for you as just a star."

"And I've always wanted to know you better as Marinette," said Adrien. "But you got so tongue-tied around me that I didn't want to embarrass you."

"That was my nervous crush talking," said Marinette. "But now I have confidence because I've been able to be at ease around you as Chat Noir."

"Let's spend more time together," said Adrien. "There's lots more to learn about our hidden depths."

"I totally agree," said Marinette.

"How about a movie? Kim and Ondine are going to see _Mecha Monkeys vs. Cyber Sharks 3_ together tonight. Want to make it a double date?"

"I'd love to," said Marinette.

 **The End**


End file.
